Questions tagged [nfc]
Near Field Communications - In antennae theory Far Field radiation is that RF energy that gets transmitted, Near Field is the RF energy that typically does not propagate , unless it is intercepted by a special antenna. It is used to transmit signals over short distances without transmitting widely, it is used in wireless communications for very short ranges on the order of meters and is harder to intercept because you have to be close.
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NFC antenna design - moving from rectangular to circular
I'm working on a design using an NXP PN7150 NFC chip with PCB antenna. My initial prototype used their online tool for the antenna design, to generate the values for the matching network, however this ...
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How many coils does an NFC tag contain?
I'm trying to wrap my head around NFC tag inner workings. In particular I'm curious whether different coils are used for harvesting energy and to transmit data. This random NFC tag IC datasheet I ...
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NFC module commands/ TagLostException
I am trying to send commands and image data to an NFC module connected to an e-paper display and keep getting TagLostException, probably meaning the command is wrong. I have asked this question on ...
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PN532 RFID Reader IC taking up 4mA even when there is no power applied
I have designed a custom PCB for one of my side projects. PN532 is interfaced with ESP32 over i2c. Goal is to have the system consume current in uAmps range when in deep sleep. I put ESP32 in deep ...
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Disable NFC tag so it does not trigger reader
Is there a way to disable (kill) the NFC tag so that it doesn't trigger the reader. Without physical intervention.
My goal here is for the smartphone not to get triggered by a disabled NFC tag. ...
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How to calculate the size of the goldcap in energy harvesting?
I want to build an NFC-transponder (NFC chip: ST25DV) which is powered over energy harvesting. How could I calculate the size of the goldcap (supercapacitor) or maybe a normal tantalum capacitor to ...
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How can I make a double-sided NFC card, where the two sides read differently?
I'm trying to create a double-sided NFC cards, where the two sides read different things. So depending on which side you hold onto your phone, you get a different result. I've tried with a sheet of ...
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Are those components mandatory?
I am building this circuit for an NFC component ST25R95 on a small PCB.
I am wondering if I can disregard the marked components on the power supply (inductors and capacitors for filtering.) These ...
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mfrc522 Arduino library -> RFID ERROR: PCD_Authenticate() failed: Timeout in communication
I'm trying to do a project using RFID tags to store information to be retrieved later with another device. Kind of a storage memory.
I've bougth several tags which I can write and read with several ...
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Impedance match an NFC antenna to 50 Ω
I have a hard time understanding how I can impedance match a homemade NFC antenna to 50 Ω.
My antenna is designed by calculating the inductance based on the dimensions, windings, and so on.
R_ant is ...
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NFC and magnet interference in a concrete piece
Do you know if both NFC and a magnet would work correctly in this scenario?
I´m designing small pieces of concrete (imagine chess pieces) with three layers: magnet inside, NFC tag in the middle, and ...
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Why is SPI described as output and UART as input in the MFRC522 datasheet?
I am currently trying to figure out why my NFC reader circuit with MFRC522 chip is not working and I stumbled upon this in the datasheet. In the section describing how to activate different digital ...
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What is a good loop probe to use for non contact measurements at 13.56MHz?
I have a receiving antenna (9 turn spiral, 1cm in diameter) that I would like to measure (inductance) wirelessly at 13.56MHz. While looking through application notes from ST and NXP semiconductors, I ...
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CCS/RF430FRL152HEVM: Trouble NFC value reading for RF430FRL152H
I am using the RF430FRL152HEVM kit for NFC communication with a mobile phone. I am building an app to read from this evaluation board and I am having trouble sending/reading an NDEF signal. I saw that ...
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Calculate inductance and capacitance of a double layer antenna (RFID)
I want to design an antenna that will work with RFID NFC chip NHS3152.
The NHS3152 IC specs are:
IC capacitance at precise measurement conditions
For this particular IC, there is a demoboard.
Since I ...
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Are there any NFC tags that act as a switch or relay?
From what I understand there is always an active (reader/writer) and a passive (tag) NFC device.
Is it possible to have an NFC tag which is part of a circuit and works as a switch or a relay?
I would ...
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Power minimization in a battery powered NFC Reader?
I have been trying to design a Battery powered NFC Reader using Quectel SC60 module with SAM interface.
So , the problem is that in the reference design, LDO is always connected to VBAT thus draining ...
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Secure Access Module (SAM) connected directly to MCU bypassing the reader IC
I have been trying to design an NFC Reader using a Quectel SC60 module with a Secure Access Module (SAM) interface.
The problem is that in the reference design, the SAM is connected directly to the ...
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Detection range of RFID with RC522/PN532
I need to read a tag in a range of about 5 to 10 cm (with 2 thin (~1 cm) layers between, one in plastic, the other in ceramic). I tested two devices: the RFID-RC522 and the PN532 (in NFC mode, reading ...
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Does the signal to the NFC antenna require shielding?
My design requires a NFC antenna to be located on a different board and due to space limitations, a uFL connector can't be placed for a mini coax connection. A flex cable solves many of the design ...
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NFC and micro memory SD card
I am not sure if this is right place for this question.
NFC bandwidth can go up to 50KB per second, and there are NFC business cards that have EPROM up to 8kb.
Is there possibility to put micro SD ...
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Clarification on amplitude of observed NFC PICC response
I am using a simple pick up coil attached to an oscilloscope (and as pictured a Saleae Logic Pro 16) to monitor the NFC traffic between a reader (PCD) and ISO15693 tag (PICC).
The reader is a PN5180 ...
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Help with electronic circuit for a bracelet that reads state from rfid tag attached to it and lights up the corresponding LED
I'd like to make a bracelet which has an RFID tag and LEDs inside of it. I made a device
(using Arduino and rc522) that will categorise people's bracelets into one of 3 categories when it touches the ...
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NFC tag antenna detection without an NFC chip
I need to build an application to detect an NFC antenna without an NFC passively powered chip.
As we know, we can detect an NFC tag by powering the NFC chip inside this tag. It will then broadcast its ...
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NFC UID max read count
Documentations indicates a maximum number of read/write of 100 000 cycles for some passive NFC tags (for ex NTAG215, NTAG216, ...)
Does this limitation apply if I only read the UID without any writes /...
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Can smartphones power a MCU circuit through an NFC tag?
NFC tags are passive devices and get their power from the NFC reader/writer. For my question, I'm specifically asking for recent smartphones as NFC readers/writers.
Does the phone transmit enough ...
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NFC antenna booster
Hi I’ll get straight to the point... theoretically if I built an antenna loop that went around a door frame including under the carpet so I could walk through the loop, then connected the antenna to a ...
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How to tell what type of RFID tag?
I have an RFID tag for access to my apartment building that I would like to clone(buying one through strata would be 100s of dollars).
I have a proxmark 3 easy and have cloned tags in the past with ...
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Can i Increase the NFC range upto 50cm by making a bigger antenna? i only want to write data into a NFC enabled EEPROM?
As NFC are active upto 15cm range, i/m using a PN532 to write data into a NXP NFC enabled EEprom, which is successful, i want to increase its range by 2X by increasing the Power or size of Antenna for ...
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Need RF advice (NFC antenna VS GND pour)
I'm currently working on a design who involve a NFC chip (ST24DV) who need to be on the board as it's used to communicate with a smartphone.
Here is the picture of the antenna:
There is a LED on the ...
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Is an RF connector required for an NFC Tag?
I have an NFC tag application that uses an external antenna. The antenna itself has not been properly selected just yet, but my question is with regards to connecting the external antenna to the NFC ...
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Using Bluetooth to rapidly connect and send data?
I have an idea for a distributed communication platform that I want to build. For my project, I would have many phones, and I would like to send ~20kb of data between each phone at a minimum range of ...
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RFID (13.56MHz) tag properties depending on read distance
In a reader design i experiencing some problems with RFID tags. I've evaluated the different tags, and they all are made equally - the tag size, tag chip type, antenna and antenna geometry are ...
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Reading multiple RFID tags at the same time
Hi I've been working on a personal project for which i need to read multiple RFID tags in close proximity, something like 10-20 tags at once, I know RIFD tags can't be actually be read at the same ...
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What to be concerned about with NFC using external antenna located off board?
Working on an NFC application (NFC tag) and it looks like the NFC antenna will be located off-board. This is a sticker type of antenna.
The concern that I am possibly having is that I need to run some ...
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RFID Tags quality control
We have mutiple same-sized, same-tech RFID Tags (Mifare Classic), in the Field we have discoverd that some tags are less readable than others. For example, the distance is smaller or it takes more ...
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Would a magnet interfere with NFC devices in this scenario?
I am thinking about manufacturing an interactive chessboard as a personal project. The circular pieces (resembling more or less poker chips in shape) would contain NFC tags, so it is possible for the ...
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Typically what range can an active powered type 5 NFC tag be written / read on iOS/Android
does anyone know the answer to the above - I am struggling to find out the information. I know that a type 5 tag can be read from 1.5 metres away in ideal conditions, but what can I expect from a ...
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Would a ground plane/traces impact NFC antenna performance?
I am building a PCB business card with an NFC chip and a WS2812B LED display (powered by a USB-C port, NFC is not connected to the LEDs). Right now I have a ground plane on the side of the antenna (...
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Read data from 125kHz tag and write into 433MHz remote
At the moment, I am opening the garage door via the 125khz key tag. I purchased a 433mhz remote. Also, I have a tool to read/write data from tags and I have used it in the past to copy key tags.
I ...
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Low latency passive RFID solution?
I'm an embedded software developer working on a personal project using RFID. I'm attempting to read a passive 13.56 MHz tag moving at 100ft/sec. Given the limited range of passive tags, I'm looking ...
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NFC Antenna Design/Matching without VNA
I would like to design a circuit around the W7002 antenna (Dataheet) and the NXP PN532 NFC Reader Chip. Since I never worked with antenna design before I do not have a VNA and I also don't have ...
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How to solder wires onto pins of an RFID chip?
I want to integrate a sensor with NXP's NHS3152 (datasheet). To do this I have to solder the wires onto the pins of the RFID chip.
What tools should I buy to do this?
What is a good reference to learn ...
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NFC - design of inductor/"antenna" made of PCB traces
I did a layout of a NFC PCB inductor/"antenna"(I know it is not one exactly) drawn only on top side copper (nothing drawn on other layers at inductor area), and I wonder if there will be a ...
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NFC 13.56MHz RF - Use inductor in place of pcb trace made antenna
I need to make a NFC antenna on NFC tranceiver->LC filter->matching circuit->antenna.
Inductance shows to be 1.5uH on an online calculator of nfc antennas. Can I simply just place a good inductor of ...
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Limiting NFC distance between reader and tag
I plan to do a PCB with an MCU and it will include one NCF reader IC + PCB antenna in the same board. I have pre-selected one of the following ICs:
Texas TRF7970A: https://media.digikey.com/pdf/Data%...
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RC522 has other pins than shown in all the tutorials
I've bought an RFID RC522 module which I intend to use with my Raspberry Pi 3B+. I read the following tutorials and I noticed that their modules have other pins than the one I bought:
https://www....
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Override value of RFID tag from external sensor
I have the following scenario, there is a RFID tag attached to a certain object which also have a light sensor on it (this is just for illustrative purposes, it could be another type of sensor), I ...
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NFC Loop Antenna placement
I'm trying to design a NFC loop antenna according to the following specification:
http://www.ti.com/lit/an/sloa135a/sloa135a.pdf
In the design the loops are placed on the top layer of the PCB, same ...
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NFC tag affected by circuit board?
total noob here. I have a general question regarding the NFC tags:
I have a 12mmx19mm NFC tag.
I notice I was able detect it (1-1.5cm away) without a problem until I place a circuit board behind it (...
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